1. Field of the Invention
The present invention relates, in general, to an Access Point (AP) for providing Wireless Local Area Network (WLAN) virtualization, a WLAN virtualization system, and a method of providing access to a wireless communication network using the AP, and, more particularly, to a WLAN virtualization system which is capable of efficiently separating a Basic Service Set (BSS) into a plurality of virtual BSSs in a Time Division Multiplexing (TDM) manner.
2. Description of the Related Art
A virtual Access Point (virtual AP) is a technology for configuring a plurality of logical APs using a single physical AP. When a plurality of virtual APs is configured using a single physical AP, it gives a large advantage in that a plurality of network services can be provided using a single AP. That is, the costs of installing and managing APs can be reduced and the problems of interference and collisions occurring when a plurality of physical APs is present can be mitigated.
For example, in the case of services in an airport, there may be a need to add a WLAN service for ordinary tourists in a situation in which a WLAN is currently being used for a computerized operation such as ticketing. In this case, user groups belonging to the two types of services require different types of authority to gain access to the network and different security levels as well. In order to provide such differential services, a virtual AP can be used instead of installing additional APs.
A conventional virtual AP technique is implemented using a plurality of Service Set IDentifiers (SSIDs). A plurality of virtual APs having different SSIDs may publicize their SSIDs and capability sets. However, in this case, a problem arises in that it is impossible to dedicate separate wireless resources to individual groups or to avoid interference between wireless service areas. That is, wireless resources and wireless services of virtual service groups cannot be isolated from each other.
In a WLAN virtualization system, restrictions occurring when wireless resources are not isolated can be described using the above example applied to the airport. For example, when a malicious user disguises himself or herself as a passenger and carries out a Denial of Service Attack (DOS attack), he or she encroaches all of the wireless resources of a relevant AP, thus resulting in airport operations being made difficult to conduct.
Meanwhile, as an example of a new application enabling performance improvements when the WLAN virtualization system virtualizes wireless resources, there is wireless backward compatibility problem. When WLAN standards are upgraded, and as a result, a conventional legacy device and a newly introduced device coexist, the problem of backward compatibility occurs. Newly established standards provide several coexistence schemes with legacy devices, for example, protection mechanisms, but it is difficult to apply such coexistence schemes to various cases, or there are a number of disadvantages in terms of cost and resource efficiency.